Development of atherosclerosis in arteries has been associated with flow disturbances and high levels of shear stress placed on the vascular endothelium. Very few models used to predict the velocity field and shear stress in the coronary arteries take into account the motion imparted on the vessel by the rhythmic beating of the heart. During each cardiac cycle these arteries are both twisted and longitudinally stretched. It is quite possible that such motion significantly affects the flow patterns within the vessel and contributes to the propensity of the coronary arteries to disease. It is the objective of this proposal to perform a preliminary investigation, using a commercially available computational fluid dynamics software package, assessing the effects of longitudinal extension and twist on the wall shear stress and flow field within a coronary artery model.